Machines such as, for example, dozers, motor graders, wheel loaders, wheel tractor scrapers, and other types of heavy equipment are used to perform a variety of tasks. Autonomously and semi-autonomously controlled machines are capable of operating with little or no human input by relying on information received from various machine systems. For example, based on machine movement input, terrain input, and/or machine operational input, a machine can be controlled to remotely and/or automatically complete a programmed task. By receiving appropriate feedback from each of the different machine systems during performance of the task, continuous adjustments to machine operation can be made that help to ensure precision and safety in completion of the task. In order to do so, however, the information provided by the different machine systems should be accurate and reliable. The position of the machine is a parameter whose accuracy may be important for control of the machine and its operations.
Conventional machines typically utilize a navigation or positioning system to determine the absolute position for the machine. Some conventional machines utilize a combination of one or more of Global Navigation Satellite System (GNSS) data, a Distance Measurement Indicator (DMI) or odometer measurement data, Inertial Measurement Unit (IMU) data, etc. In addition to having mechanisms for determining absolute position, conventional machines also include mechanisms such as RADAR sensors, SONAR sensors, LIDAR sensors, IR and non-IR cameras, and other similar sensors to determine relative pose between two or more machines. Pose, as used in this disclosure, refers to both position and orientation. However, conventional machines do not utilize this relative pose information to refine their absolute position and derive a more robust and accurate measure of their absolute machines.
An exemplary system that may be utilized to determine the relative position of a first machine with respect to a second machine is disclosed in U.S. Pat. No. 8,026,848 (“the '848 patent”) to Hanson. The system of the '848 patent determines the relative position by utilizing radios. Specifically, the '848 patent utilizes the time of flight of a radio signal to determine the relative position. Although the system of the '848 patent may be useful in determining the relative positions of two machines, the system does not go further and utilize this information to determine or further refine an absolute position measurement for the machines.
The positioning system of the present disclosure is directed toward solving one or more of the problems set forth above and/or other problems of the prior art.